Avaliação da união composito/dentina em função do tempo de condicionamento acido e sistema de união em dentes deciduos

Orientador : Regina Maria Puppin RontaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Este estudo teve por objetivo avaliar a resistência da união à microtração, o padrão de fratura obtido após o ensaio mecânico e a região da união compósito/dentina, em função de tempos de condicionamento ácido (7, 15 e 20s) e sistemas de união (Single Bond-SB; Prime & Bond 2.1 - P&B2.1; One Up Bond F-OUP e Clearfil SE Bond-CSE). Foram selecionados 138 molares decíduos, hígidos, extraídos por indicações ortodônticas, de crianças na faixa etária de 4 a 9 anos. Para o ensaio de resistência da união à microtração, foram selecionados 48 dentes, aleatoriamente distribuídos em 3 grupos de acordo com o tempo de condicionamento ácido e subdivididos em 4 subgrupos de acordo com o sistema de união, sendo (n=20): G1- 7s + SB; G2- 15s + SB; G3-20s + SB; G4- 7s + P&B2.1; G5- 15s + P&B2.1; G6- 20s + P&B2.1; G7- 7s + OUP; G8- 15s + OUP; G9- 20s + OUP; G10- 7s + CSE; Gll- 15s + CSE; G12- 20s + CSE. Os dentes foram transversalmente cortados na superfície oclusal, planificados até a obtenção de área plana em dentina. Os procedimentos de união foram realizados de acordo com a distribuição dos grupos, e a superfície restaurada com compósito odontológico Filtek Z250. Em seguida, as amostras foram cortadas nos sentidos vestíbulo-lingual e mésio-distal, para obtenção de corpos-de-prova com área de secção de aproximadamente 1mm2. Após o armazenamento por 24h, os corpos-de-prova foram submetidos ao ensaio de microtração em máquina de ensaio universal (Instron) à velocidade de O ,5mm/min. Os dados foram submetidos à Análise de Variância e ao teste de Tukey). Após o ensaio mecânip,p,fodos os corpos-de-prova foram analisados quanto ao tipo de fratura em Microscópio Estereoscópico (X25) e, os compósito/dentina foram selecionados 90 dentes, distribuídos e tratados como descrito anteriormente, exceto que apenas um corte no sentido vestíbulo-lingual foi realizado, para posterior preparo para análise em MEV. As fotomicrografias foram analisadas segundo os escores: O - ausência de camada híbrida e prolongamentos resinosos; 1 - ausência de camada híbrida e presença de prolongamentos resinosos; 2 - presença de camada híbrida e ausência de prolongamentos resinosos, e 3 - presença de camada híbrida e prolongamentos resinosos. Os dados obtidos foram submetidos à análise estatística (Teste de Kruskal-Wallis). De acordo com os resultados pôde-se concluir que: 1 - A diminuição no tempo de condicionamento ácido (7s) não interferiu nos valores de resistência da união compósito/dentina, para todos os sistemas de união utilizados neste estudo; 2 - Houve correlação negativa, apenas, entre a interação P&B2.1*tempo de condicionamento; 3 - A análise do padrão de fratura demonstrou maior predominância de falhas mistas para todos os grupos, exceto P&B 2.1, cujas falhas encontradas para os tempos de 7 e 15s foram adesivas e para o tempo de 20s coesiva em compósito; 4 - Quanto ao aspecto morfológico da união compósito/dentina pôde-se observar que a formação de camada híbrida e prolongamentos resinosos mostrou relação direta com o sistema de união utilizadoAbstract: The aim of this study was to evaluate the micro-tensile bond strength, the failure sites obtained after the test, and the resin/dentin interface, in different etching times (7, 15, and 20s) and with different bond systems (Single Bond-SB; Prime & Bond 2.1- P&B2.1; One Up Bond F-OUP e Clearfil SE Bond-CSE). 138 sound extracted primary teeth were selected. For the micro-tensile bond strength, 48 teeth were selected and randomly distributed into 3 groups, according to etching time, and subdivided into 4 subgroups, according to bond systems as follows (n=20): G1- 7s + SB; G2- 15s + SB; G3- 20s + SB; G4- 7s + P&B2.1; G5- 15s + P&B2.1; G6- 20s + P&B2.1; G7- 7s + OUP; G8- 15s + OUP; G9- 20s + OUP; G1Q- 7s + CSE; Gll- 15s + CSE; G12- 20s + CSE. The teeth were obliquely cut on the occlusal surface and flatenned until dentin area was reached. The bonding procedures were carried out according to groups, and the restorative procedure was carried out using the resin composite Filtek Z250. Next, the samples were sectioned in buccal-lingual and mesio-distal orientations, to obtain samples of about lmm2. The samples were stored in distilled water at 3-rC for 24h, and then submitted to micro-tensile bond strength in a Universal Testing Machine (Instron) with a crosshead speed of 0.5mm/min. The data were submitted to ANOV A and Tukey's test (p<0.05). The failure sites obtained after the test were observed, for failure type, in stereoscope microscopy of 25X magnification, and the representative failures of each group were observed in Scanning Electron Microscopy (SEM). 90 teeth were selected for the analysis of resin composite/dentin. The teeth were distributed and treated as previously described, except that just one. The photomicrographs were analyzed according to scores: o - absence of hybrid layer and resin tags; 1- absence of hybrid layer and presence of resin tags; 2 - presence of hybrid layer present and absence of resin tags, and 3 -presence of hybrid layer and resin tags. The data obtained were submitted to Kruskal-Wallis's testo According to the results it could be concluded that: 1 -the decrease in etching time (7s) did not interfere in bond values, for ali bond systems used; 2- there was negative correlation, solely, between P&B2.1*etching time interaction; 3 - the pattern of failure analysis showed major predominance of mixed failures for ali groups tested, except P&B 2.1, where failures for 7 and 15s were adhesives and for the 20s were composite cohesive; 4 - the resin composite/dentin area showed that the formation of hybrid layer and resin tags showed direct relation with the bond system used.MestradoMateriais DentariosMestre em Ciência

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (

Eficácia da adesão em dentes decíduos

O objetivo deste trabalho é discutir os aspectos envolvidos na eficácia da adesão em dentes decíduos, através da revisão de literatura. Pode-se concluir que o processo de adesão é um fenômeno complexo, que sofre a influência direta das propriedades físico-químicas do adesivo e do aderente. Sendo o substrato, dentina de dentes decíduos, morfológica e quimicamente diferente dos permanentes, o processo adesivo apresenta-se diferenciado para ambos os tipos dentais: o condicionamento ácido em dentina de dentes decíduos ainda se encontra sem um protocolo estabelecido, porém sabe-se que este substrato apresenta-se mais reativo aos ácidos do que os permanentes; quanto maior o tempo de exposição deste substrato ao condicionamento ácido, menores sendo os valores de resistência de união; os dentes decíduos apresentam a camada híbrida mais espessa que os dentes permanentes, e quanto menor a espessura da camada híbrida melhores resultados do processo adesivo. Ainda, a influência da remoção do colágeno sobre os valores de resistência de união, realizada pelo condicionamento superficial, não se encontra definida. A umidade dentinária altera os valores de resistência de união, porém tais estudos foram realizados somente em dentes permanentes, e mais estudos devem ser realizados principalmente para evidenciar sua influência em dentes decíduos. Quanto ao meio de armazenamento e a termociclagem, eles parecem não alterar os valores de resistência de união, para a maioria dos autores estudados. Então um protocolo específico para o processo adesivo em dentes decíduos deve ser estabelecido, com o objetivo de se alcançar valores de resistência de união tão satisfatórios quanto os encontrados para dentes permanentes.This work was carried out to discuss the efficacy of the adhesion in primary teeth by the literature review. lt can be concluded that the adhesion process is a complex occurrence which can be directly influenced by the phisico-chemical properties of the adhesive and the adherent. As the primary dentin is a different substratum compared to the permanent dentin due to its morphological and chemical contents, the adhesive process in these kinds of teeth happens to be different. The acid etching in primary dentin has not yet been defined. Nevertheless, it is known that primary dentin is more affected by acid etching than the permanent one. The longer the dentin is exposed to the acid, the lower the shear bond strength (SBS) values will be. The primary teeth showed a thicker hybrid layer when compared to the permanent dentition. However, the lower the hybrid layer thickness, the better the results achieved in the adhesive process. Besides, the influence of collagen removal on the SBS values due to the superficial etching has not been defined, yet. Some studies demonstrate that dentin moisture alters the values of bond strength, however, these studies have only analyzed the permanent teeth. Therefore, other studies need to be done mainly to illustrate its influence in primary teeth. Storage and thermocycling do not seem to alter the SBS values according most of the authors. Thus, an specific protocol should be established to the adhesion process in primary teeth in order to reach the similar SBS values to primary and permanent teeth

Procedimentos de união em esmalte e dentina de dentes decíduos

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia.Este estudo teve por objetivo avaliar o desempenho de procedimentos de união, em esmalte e dentina de dentes decíduos, por meio da avaliação da microinfiltração, em um modelo que inclui ciclagem de pH, possibiltando observar a qualidade do procedimento de união em condições que simulam o processo des-re, com o intuito de se verificar qual protocolo de união é mais adequado para dentes decíduos. Baseado nos dados obtidos pôde-se concluir que: a alteração do protocolo de união não interfere negativamente nos resultados; não se pôde observar associação entre microinfiltração e presença de lesão cariosa na interface dente/restauração, e nenhum procedimento de união foi capaz de impedir a microinfiltração

Effect of storage time and chlorhexidine addition on the mechanical properties of glass ionomer cements

o evaluate the effect of the chlorhexidine (CHX) incorporation and the storage time on the mechanical properties of glass ionomer cements (GICs). Methods: The following GICs were evaluated: Ketac Molar Easymix (KM), Vidrion R (VR) and Vitromolar (VM), containing or not CHX. GIC liquid was modified by adding 1.25 % CHX digluconate and then manipulated with the power and placed into the stainless steel cylindrical or bar-shaped molds. GICs specimens were stored into water for 1, 7 and 28 days. After these periods, specimens were submitted to flexural, diametral tensile and compressive strength tests, according to ISO standards. Data from mechanical tests were statistically analyzed using 2-way ANOVA and Tukey tests. Results: Overall, the storage time did not influence any of the mechanical properties of the GICs tested. In contrast, the inclusion of CHX reduced significantly these properties for all GICs tested. KM presented the highest values of compressive strength for all storage times. KM + 1.25% CHX had lower compressive strength results than KM, however, it showed similar results when compared to another GICs without CHX. Conclusions: The presence of chlorhexidine, independent of the storage time, interfered on the mechanical characteristics of GIC

Dental caries in inland Brazilian adolescentes and its relationship with social determinants

identify the prevalence of dental caries in inland Brazilian adolescents, and to analyze the influence of socio-demographic and clinical variables, and access to dental service on caries experience. Methods: This study had a non-probabilistic sample comprising 504 adolescents aged 12 years, attending public schools in the city of Nova Friburgo, mountain region of Rio de Janeiro, Brazil. The World Health Organization (WHO, 1997) criterion was used by previously calibrated examiners to report dental caries. Variables were obtained by means of a semi-structured questionnaire applied to the adolescents parents. Results: The D3 MFT mean was 1.90 and the Significant Caries (SIC) Index was 4.54, mainly represented by the carious component. Multiple logistic regression analysis revealed that parents with over 8 years of schooling (OR=0.579), absence of pain (OR=0.396) and not visiting the dentist (OR=0.270) might suggest protective factors against the disease; the possible risk factors were male gender (OR=1.982) and pain, extraction and others were reasons for consultation (OR=2.435). Conclusions: Although the prevalence of caries was slightly below the national mean, polarization of the disease was clearly observed. Education and no access to the dentist led to protection against the disease. These results may contribute to planning of oral health actions directed towards this target population for the control of caries

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations

Conhecimentos e práticas em saúde bucal com crianças hospitalizadas com câncer Knowledge and practices of oral health on hospitalized children with cancer

O objetivo do estudo foi avaliar os conhecimentos e práticas em saúde bucal (SB) com crianças hospitalizadas com câncer. A amostra foi composta pela equipe de enfermagem, cuidadores e crianças. Foi aplicado um questionário relacionado ao conhecimento geral sobre SB, métodos e instrumentos utilizados para a higiene oral (HO) e dados socioeconômicos. Baseado nos resultados, quem realiza a HO das crianças são os cuidadores (90,7%), que receberam orientações da equipe de enfermagem em 21,4% dos casos. Com relação ao desconforto na cavidade bucal, a equipe de enfermagem reportou que todos apresentaram manifestações clínicas, enquanto apenas 62,8% dos cuidadores reportaram casos. Todos os participantes consideram importante haver um CD no setor de oncologia. Pôde-se concluir que não existe um protocolo de cuidados com a higiene bucal de crianças hospitalizadas com câncer e que as manifestações bucais mais frequentes entre os pacientes em tratamento antineoplásico foram: mucosite, enjoos, vômitos, xerostomia e ausência de paladar.<br>The aim of this study was to evaluate the knowledge and practices of oral health (OH) in hospitalized children with cancer. The sample was composed by the nurse team, caretakers and children. It was applied a questionnaire concerning the general knowledge about OH, methods and instruments used for oral hygiene (OH). According to the results, the responsible of OH of children are the caretakers (90.7%) who receive instructions from the nurse team in 21.4% of cases. As for the oral cavity discomfort, the nurse team reported that all patients exhibited clinical manifestations while the caretakers reported a different number, 62.8% of cases. All participants considered important having a dentist in the oncology sector. According to the results obtained, it was possible to conclude that there is no oral health protocol for hospitalized children with cancer and that the most frequent oral manifestations among patients going through antineoplastic treatment were: mucositis, nausea, vomit, xerostomy and lack of sense of taste